New Orleans--Practice makes perfect--but for some musicians, too much practice cramps their hands so badly that they can no longer play their instrument. The condition, called focal dystonia, can afflict typists or anyone else who makes repetitive, forceful, precise movements. Most treatments focus on fingers, hands, and arms. But a study presented here today at the Society for Neuroscience's annual meeting shows that the brain may be to blame. Retraining the brain can allow musicians to play again.

Over the past decade, neuroscientists have begun to believe that the adult brain is malleable. For instance, in the parts of the brain that register sensations, every finger has its own designated spot; but if you tape an index and middle finger together for a few weeks, these spots converge, and one brain region will start communicating with both fingers. If, after this rewiring, you touch someone on the middle finger when they're not looking, they might claim you touched the index finger.

Rewiring also happens naturally, says neuroscientist Thomas Elbert of the University of Konstanz in Germany. He worked with 18 musicians--guitar players, wind players, and pianists--who had suffered from painful, debilitating hand cramps for years, and who hadn't been helped by traditional physical therapy. Using brain images called magnetic encephalograms, his team found that the finger maps in the sensory cortex of the musicians' brains were smeared together; the fingers sent signals to overlapping cortex areas. While their fingers were thus less coordinated, the musicians kept forcing their way through complex movements--which ultimately left them in pain, Elbert proposes.

Elbert then trained the musicians to do simple exercises in which they moved one finger at a time, for about an hour each day. They all responded well to the treatment. After about a week, they regained flexibility and coordination, and some could play their instruments as well as they once could. When Elbert scanned their brains, their sensory cortex looked normal.

Why does intensive practice on an instrument cause the brain's sensory areas to become scrambled? "What fires together, wires together," says neuroscientist Michael Merzenich of the University of California, San Francisco. The musicians were probably moving their fingers so quickly that the brain couldn't tell one finger's signal from the next, he says. Elbert's simple, single-finger movements taught the brain the difference between the fingers once again. Because focal dystonia is a problem of mislearning, Merzenich says, "you have to learn your way out of it."